A Physiologically Based Modeling Approach to Evaluate Intravenous Levetiracetam Dosing in Term and Preterm Neonates

Area of Science:

• Neonatal Neurology
• Pharmacokinetics
• Drug Development

Background:

• Neonatal seizures are common, with phenobarbital causing adverse effects.
• Levetiracetam is a safer alternative, but optimal neonatal dosing is unknown.
• Current weight-based dosing may be inappropriate for preterm neonates.

Purpose of the Study:

• To develop a physiologically based pharmacokinetic (PBPK) model for levetiracetam in term and preterm neonates.
• To evaluate pharmacokinetic differences between term and preterm neonates.
• To inform optimal levetiracetam dosing strategies for neonatal seizures.

Main Methods:

• Developed a PBPK model for levetiracetam in neonates.
• Accounted for physiological changes affecting drug distribution and clearance.
• Extrapolated renal and metabolic clearance using allometric scaling and age-dependent corrections.

Main Results:

• A 1.56-fold increase in tissue distribution was needed for neonates.
• Renal clearance required a 61% increase in term neonates.
• In preterm neonates (<37.5 weeks), renal clearance was the primary elimination route, with metabolic clearance near zero.
• Simulations indicated higher plasma concentrations in more premature neonates, potentially exceeding toxicity thresholds.

Conclusions:

• Standard levetiracetam dosing may lead to toxicity in preterm neonates.
• Lower weight-based dosing is likely needed for preterm infants.
• PBPK modeling is crucial for understanding and optimizing neonatal drug dosing.